Block-signal system.



R. W. TAYNTON.

BLocK SIGNAL SYSTEM.

APPLIOATION FILED 00T.19, 1908. 925,61 1 Patented June 22, 1909.

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BLOCK SIGNAL SYSTEM.

APPLIOATION FILED oom-19, 190e.

925,61 1. Patented June 22, 1909.

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BLOCK SIGNAL SYSTEM.

APPLICATION FILED 0(1T.19, 1908.

925,61 1. Patented June 22, 1909.

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ROBERT W. TAYNTON, OF TAOOMA, WASHINGTON.

BLOCK-SIGNAL SYSTEM.

Specication of Letters Patent.

Patented June 22, 1909'.

Application filed October 19, 1908. Serial No. 458,513.

To all whom it may concern:

Be it known that I, ROBERT IV. TAYNTON, a citizen of the United Statesof America, residing at rlacoma, in the county of Pierce and State of/Vashington, have invented certain new and useful Improvements in Block-Signal Systems, of which the following is a specification, referencebeing had therein to the accompanying drawing.

This invention relates to devices for controlling the operation oftrains and has for its objects to provide means for safeguarding thetrains against errors or carelessness or inefficiency of the nienoperating the controlling apparatus, in that both operators at the endsof a block must coperate in allowing a train on the block, and thereceiving operator controls the sending operator, and when a block hasonce been set to allow a train thereon it cannot be released to all-owany other train in either direction until the rst train has passed offtherefrom since all the controlling apparatus is automatically locked inthe position for allowing said train to pass thereon.

My invention as herein illustrated is intended to be operated inconnection with an interlocking semaphore system of signals whereby thetrain crew are given orders and also in connection with suitable safetyswitch apparatus. y

The apparatus is arranged for the control of a single track line ofrailroad and is illustrated in the accompanying drawings, in which,

Figure l is a diagrammatic representation of the apparatus controllingtwo blocks of railroad, showing' one of said blocks clear while theother is occupied by a train thereon; Fig. 2 is a front view (with coverremoved) of the indicator located in the controlling tower, one of saidindicators being provided for each end of each block, and the partsillustrated in this view are shown in their positions when a train isapproaching the tower; Fig. 3 is an exterior view of said indicatorshowing the index thereof in the position assumed when a. train isreceding from the tower; and Fig. 4 shows the indices in the positionsassumed when the block is clear; Fig. 5 is a view.vof a portion of thesending switch controlling one of the circuits and in the positionassumed thereby when the line is clear or when a train is approaching,and electrically locked in said position; Fig. G is a side view of themechanical interother; Figs. 7 and 8v are diagrammatic views n showingrespectively the receiving and sending switches, and their tumblers, inthe positions assumed when a train is receding wherein the receivingswitch is not locked by the electric lock, while the sending switch islocked thereby; and Fig. 9 is a view similar to Fig. 6 wherein thetumblers are in the same positions as in Figs. 7 and 8 and where` in thetumbler of the receiving switch is mechanically locked by the tumbler ofthe sending switch; Figs. l0, ll and 12 are similar to Figs. 7, 8, and 9respectively except that the parts therein are in their positions forreceiving a train on the block wherein both switches are lockedelectrically and the sending switch is locked mechanically.

Similar characters of reference refer to similar parts throughout theseveral views.

Referring now to Fig. l it is seen that two blocks A and B are shownbetween stations l, 2 and 3 and that a single track extendstherebetween. rIwo telegraph wires 4, 5 extend between the stations,being connected to the circuit controlling switches therein in thehereinafter described manner. Before proceeding' with a detailed accountof the instruments, however, I shall point out that the instruments inthe stations are similar (are duplicatesv in fact) and that therefore adescription of one will be understood to apply to all, andthat thereforethey will all be similarly indicated by corresponding numerals orletters of reference, but that where, in describing their action under acertain set of circumstances, I have to call attention to the block andstation in which the part being mentioned is located, I shall do so bysuifixing in parentheses to the reference numeral, the block letter andstation number; for instance, the part l2 injthe instruments for blockB, in station 2, will be indicated part 12 (13.2) while the same part inthe instruments for block B, in station 3, will be indicated part l2(13.3). Similarly the telegraph wires for block A will be described as 4(A) and 5 (A) while thoseof block B will be described as 4 (B) and 5 iOne end of the line wire 4 is connected in one station to the pivot ofthe electric sending switch 6, and the other end thereof is connected inthe other station to the pivot of the electric receiving switch 7 g andthe ends of the line wire 5 are similarly connected to the receiving andsending switches 7 and 6 respectively in the same stations.

Referring principallyto Figs. 1 and 5y it isseen that the switches 6 and7 each consist of a pair of flat arms 8 and 9 arranged about the pivotin such manner that when one arm 8 is thrown into contact with asuitable terminal the other arm 9 is out of engagement with itsterminal. A handle 10 is formed in convenient position so that saidswitch may be readily operated. An extension 11 is also provided in suchplace as to be engaged by one or the other of a pair ef electricallyoperated stops or lock bars in the case of the sending switch 6, whilein the case of the receiving switch 7 there isonly one of the said stops(Figs. 7 and 10). The electric lock for the receiving` switch 7 consistsof a solenoid 12 adapted to draw a plunger or core toward it and thusturn the lock bar 13 engaged thereby on its pivot in such manner thatits other end will engage the extension 11 to prevent the switchV beingmoved from the receiving position (shown in Fig. 10) so long as acurrent is energizing the solenoid 12. The electric lock for the.

sending switch 6 (Fig. 5) consists of two independent solenoids 14 and15 actuating independent lock bars 16 and 17 respectively which arepivoted centrally under the pivot of the switch 6 in such manner thatwhen the switch is in the line clear or receiving position (Figs. 5 and11) the solenoid 14 actuates the lock bar 16 and draws it into positionto engage and lock the extension 11 of the switch so that it cannot bemoved so long as the solenoid 14 is energized; and so that when theswitch is in the sending position (Fig. 8) the solenoid 15 actuates thelock bar 17 to lock the switch so that it cannot be moved out of thisposition so long as the solenoid 15 is energized. The solenoids 12, 14and 15 are similar in all respects and actuate the lock bars 13, 16%and17 against the action of some force, such as a spring or weight, whichwithdraws the said lock bar when the solenoid controlling it is nolonger energized. In Fig. 1 the solenoids are shown out of their properpositions, each one being adjacent to the terminal in contact with whichit locks the arm of the switch; this is done to simplify the drawingwhich is intended primarily to show the electric circuits.

The switch G is connected, by means of a rod 18, to an arm 19 secured ona rocking shaft 2O on which the tumbler 21 is mounted. The switch 7 issimilarly connected by the rod 22, arm 23, and rocking shaft 24, to thetumbler 25. The shafts 2() and 24 are suit* ably mounted parallel witheach other and the tumblers 21 and 25 thereon are in the 'gto the right(Fig. 10)

same plane. The tumblers are similar in shape but are mounted in theshafts in in verted positions and are of such form and dimensions thatthey coperate with each other in the following manner :-Each tumblerconsists of a tail part 26 whose inner surface is curved so that whenthe -tumbler is in its line clear or unlocked Y position (Fig. 6), thesaid surface is con centric with the shaft of the other tumbler; andalso of a shoulder 27 which engages the said tail 26 in said unlockedposition and which has a curvature of equal radius about the center ofthe shaft on which said tumbler is mounted. Each tumbler is alsoprovided with a nose or hook 28 which eX- tends out from the shoulder 27and which engages the tail 26 of the other tumbler when it (the firsttumbler) is rocked into its locking position (Figs. 9 and 12). It willbe seen from the drawings that, when the switch handles 10 are bothpushed to the left, the tumblers are in the unlocked position shown inFig. G and the sending switch 6 (Figs. 5 and 11) is locked by the bar 1Gcontrolled by the solenoid 14 while the receiving switch' 7 (Fig. 7) isnot locked either mechanically or electrically. Also, that if thereceiving switch 7 is thrown over it locks the sending switch 6mechanically (Fig. 12) and is itself locked electrically by the bar 13actuatedV by the solenoid 12 (Fig. 10). Also, that when the switches arethus locked it will be impossible to alter them while the solenoid 12 isenergized. Also, that if the sending switch 6 is thrown over to theright 8)V it locks the receiving switch 7 mechanically (Fig. 9) and isitself locked electrically by the bar 17 actuated by the solenoid 15(Fig. 8). Also, that when the switches are thus locked it will beimpossible to alter them while the solenoid 15 is energized.

Referring now to the electric circuits between the switches G and 7 andthe indicator. One pair of switches 6 and 7 is provided for eachindicator instrument. The

switch 6 has two terminals 29 and 30, and the switch 7 has two terminals31 and 32.

The wire 33 joins the terminal 29 with the upper right-hand solenoid 34and the wire 35 connects the said solenoid 34 to the line battery 3G,the other terminal of which is grounded. The wire 37 joins the terminal30 with the lower right-hand solenoid 38 and the wire 39 connects thesaid solenoid 38 to the ground. The wire 40 joins the terminal 31 withthe upper left-hand solenoid 41 and the wire 42 connects the saidsolenoid 41 to the ground. The wire 43 joins the terminal 32 with thelower lefthand solenoid 44 and the wire 45 connects the said solenoid 44to the line battery 36, the other terminal of which is grounded. Thus itwill be seen that the solenoids 38 and 41 in each indicator are groundedand that the solenoids 34 and 44 are connected to the line battery inthat station. Therefore if the switches 6 and 7 are both thrown over tothe line clear positions (as in block B, Fig. 1) so that the arms 8thereof engage respectively the terminals 29 and 3l then a current ofelectricity will pass from the line battery 36 (13.2) by way of wire 35(13.2), solenoid 34 (B.2), wire 33 (B2), terminal 29 (B2), arm 8 (B 2),pivot of switch 6 (13.2), line wire 5 of the block B to pivot of swith 7(B3) of the other station of' the same block B, arm 8 (13.3), terminal31 (B3), wire 40 (B3), solenoid 41 (B3), and wire 42 (13.3 to theground. Similarly another current of electricity will pass from the linebattery 36 of the other station over a precisely similar course, by wayof the line wire 4, through the solenoid 41 (B.2)

to the ground. But if the sending switch 6 is thrown in one station andthe receiving switch 7 is thrown in the other station we have acondition illustrated in block A (Fig.

1) in which the current passes from the receiving station (A.1) to thesending station (A.2) over both line wires 4 (A) and 5 (A) as followsr-It leaves the line battery 36 (A1) by the wire 45 (A.1), solenoid 44(Al), wire 43 (A 1), the terminal 32 (Al), arm 9 (A l), pivot of switch7 (Al),

line wire 4 (A), pivot of switch 6 (A.2), arm 9 (A.2), terminal 30(A.2), wire 37 (A.2), solenoid 38 (A.2), and wire 39 (A.2)

to the ground; and also from the same battery 36 (Al) by the wire 35(A.1), solenoid 34 (Al), wire 33 (A.1), terminal 29 (Al), arm 8 (Al),pivot of switch 6 (A1), line wire 5 (A), pivot of switch 7 (A.2), arm 8(A.2), terminal 31 (A.2), wire 40 (A.2), solenoid 41 and wire 42 (A.2)to the ground.

It will be noted that the course of the current in the latter part ofthe above description is the same as the course of the current in a lineclear case. 1t will also be noted that the switch 6 (A.1) is lockedmechanically by switch 7 (A l) (Fig. 12) and also electrically bysolenoid 14 (Al) (Figs. 5 and 1l) while switch 7 (Al) is lockedelectrically by solenoid 12 (Al) and is not otherwise locked; and alsothat switch 6 (A.2) is locked electrically by solenoid 15 (A.2) (Figs. 5and 8) and locks switch 7 (A.2) mechanically (Fig. 9) and that saidswitch 7 (A.2) is not otherwise locked. 1f the current energizing thesolenoid 12 (A l) be broken, then switch 7 (Al) may4 be thrown back tothe line clear position, and if this be done the circuit of the linewire 4 (A) is broken and both ends thereof are grounded; this willresult in the demagnetization of the solenoids 44 (A.l) and 38 (A.2) thebreak in this circuit also results (as hereinafter described) in thedemagnetization of the solenoid 15 (A.2) thus releasing the electriclock of the switch 6 (A.2) and allowing it to be thrown back to its lineclear position, and if this be done the tumbler secured thereto willrelease the tumbler secured to the switch 7 (A.2) and the switches forblock A will make the connections above described for line clear onblock B.

Referring now to Figs. 2, 3 and 4 the indicator comprises a box 46,preferably mounted vertically and having an indicator window 47, in itsfront face, through which the index is observed. Within this box 46 aremounted the four solenoids 34, 38, 41 and 44, the solenoids 34 and 41being vertically over the solenoids 38 and 44. They are all arrangedwith their magnetic axes vertical and the pairs are similar in allrespects. The pair of solenoids 34 and 38 is provided with a singlearmature consisting of the soft iron bar 48 which passes from one to theother. The index lever 49 engages the bar 48 at its middle point and ispivoted at 50 and carries the index card 51 at such point thereon as toswing in front of the indicator window 47 when the bar 48 is drawndownward by the solenoid 38, but to swing away therefrom when it isdrawn upward by the solenoid 34 as is shown in Fig. 2. The index card 51carries the legend train going and is colored green. The index lever 49is counterbalanced by a weight 52. Similarly the solenoids 4l and 44have an armature bar 53 engaging an index lever 54 pivoted at 50 andcarrying an index card 55 in a position similar to the card 51. The cardbears a legend train coming and is colored red. The lever 54 iscounterbalanced by a weight similar to the weight 52. I prefer to placethe pivot 50 between the pairs of solenoids so that one card will swingto one side of the window 47 and the other card will swing to the otherside thereof. A fixed index card 56 is mounted opposite the indicatorwindow 47 and in a plane to the rear of the planes of the cards 51 and55. This card 56 bears the legend line clear and is colored white. Thiscard 56 cannot be seen if either of the other cards 51 or 55 is swunginto indicating position at the window 47. The operation of thisindicator will be readily understood as follows Only one solenoid ofeach vertical pair can be energized at a time, and whichever solenoid isenergized will attract the armature bar in its direction and this barwill cause the index lever engaging it to swing on its pivot. Now ifeither of the upper solenoids is magnetized it will cause the cardcontrolled thereby to be withdrawn from the indicator window, while ifeither of the lower solenoids is energized it will cause its card toswing in front of the indicator window.

them. Y

A counterbalanced relay armature 57 is pivoted adjacent to the solenoid34 so that when the solenoid is energized the said armature willcomplete a relay circuit 58, but when the solenoid is deinagnetized thesaid Yrelay circuit will be broken. The relay circuit 58 extends fromthe relay battery 59,

through the armature 57, the solenoid 144 (which locks switch 6 in theline clear position) and back to the battery. Another relay armature 60is mounted adjacent to the solenoid 38 so that when the solenoid is-lenergized the said armature 60 will com-jv plete the relay circuit 61,whichris otherwise i The circuit 61 also extends from the battery 59,through the armature 60, the solenoid 15 (whichf locks switch 6 insending position) and back y broken by this armature.

to the battery. A third relay armature 62 is mounted adjacent to thesolenoid 44 so that when the solenoid is energized the said armature 62will complete the relay circuit v63, which is otherwise broken by thisarmature. The relay circuit 63 extends from the battery 59, through thearmature 62, the solenoid 12 (which locks the switch 7 in receivingposition) the train-break 64, and back to the battery. The train-break64 consists of any of the well-kiiown devices which are set manually butbroken by a train passing thereover in the proper direction. In thiscase I set the train-break by means of the usual visual semaphoreapparat-us.

It is evident from the foregoing that, once a train has been admitted toa block, the signals and switches thereon cannot be altered until saidtrain passes over the train-break 64 thus breaking the circuit 63, andunlocking switch 7. Also, if the line is clear, a train cannot beadmitted to a block by the sending operator because his sending switch 6is locked electrically by the solenoid 14 which is controlled by thecurrent in the line wire from the receiving switch 7 at the other end ofthe block, hence the sending operator must request the receivingoperator to throw his receiving switch 7 (which is not locked) and whenhe does so he breaks the circuit in solenoid 34, releasing the relayarmature 57, breaking the relay circuit 5S and demagnetizing solenoid14, thus releasing the sending switch 6 which may then be thrown toallow the train on the block. When this switch 6 is thrown the currentin two consecutive blocks is as follows Supthe wires 4 and 5 causes thesending switches in both stations and the receiving switch in thereceiving station to lock the switches in position, while the receivinglswitch is locked mechanically (Figs. 7, 8 and 9).

From the foregoing description it will be seen that the sequence ofoperations which takes place while a train is passing through posing atrain to be in block A and running from station 1 to station 2, andconsidering 2 the sequence of operations in block B. The

operator in station 2, having accepted the train in block A, and beinginformed that the train approaches his station 2, iininediately signalson block B to the operator of station 3, informing him thata train isapproaching station 2 and asking the said operator (station 3) to acceptthe train on block B. It must be remembered that the sending switch 6(B2) is locked by the solenoid 14 (B.2) and that the circuit of saidsolenoid 14 (B2) is controlled by the current passing from station 3,through the terminal 3l (B3), the receiving switch 7 (B3), over theline-wire 5 (B). As soon then as the operator of station 3 decides toallow the said train on the block B he pulls his switch 7 (B.3), whichis not locked electrically or mechanically, and this act causes thetumbler 25 (B3) to lock the sending switch 6 (B3) and also breaks thecontrolling circuit in the line wire 5 (B), therefore permitting theoperator of station 2 to pull his sending switch 6 (B.2) and make readyfor the train to pass through his station from block A on to block B.The act of pulling the sending switch 6 (B2) causes the tumbler 21 (B2)thereof to lock the re- 105 ceiving switch 7 (B.2) and also completesthe circuit in the line wire 5 (B) and causes the circuit containing thesolenoid 12 (B3) to the lock receiving switch 7 (B3) in its receivingposition; it also causes the circuit 110 containing the solenoid 15 (B2)to lock the Y sendingrswitch 6 (B2) in its sending position. This actalso causes the index cards 51 (B.2) and 55 to swing before theirrespective windows 47 (B.2 and B.3) indi- 115 cating that the block B isset for a train to pass from station 2 to station 3 thereover. The trainis therefore free to enter the block B from the block A and it isimpossible for the operators of block B, stations 2 or 3, to 120 alterthe signals so as to allow a train to enter the same block B from theopposite direction, that is from station 3. The train then passes overblock B, from station 2 to 3 and on arriving at station 3 it breaks the195 circuit of the solenoid 12 (B3) at the trainbreak 64 (B.3) thusunlocking the receiving switch 7 (B3). 'Ihe signals however remainunchanged until the operator of station 3 pushes the receiving switch 7130 into the line-clear position. This act neu-l tralizes the line wire5 (B) and releases the solenoid 15 (B2) so as to unlock the sendingswitch 6 (B2) and allow the operator of station 2 to throw the saidswitch into line-clear position, and by so doing the circuit through theline-wire 5 (B) is again completed and the solenoid 14 (B2) energized tolock the said switch G (B2) in this line-clear position.

Having described my invention what I claim is l. In a system for traincontrol; the combination of an electric circuit comprising a generatorin one station, one terminal ofA said generator being grounded, a linewire to the other station, and a ground to the line wire in the otherstation; a sending switch interposed in said circuit in one station; areceiving switch interposed in said circuit in the other station; andelectrically operated locking means, controlled by the currentI in thesaid circuit and adapted to lock said sending switch on said circuit,whereby said sending' switch is prevented from movement unless saidreceiving switch breaks said circuit.

2. In a system for train control; the combination of an electric circuitcomprising a generator in one station, one terminal of said generatorbeing` grounded, a line wire to the other station, and a ground to theline wire in the other station; a sending switch interposed in saidcircuit in one station; a receiving switch interposed in said circuit inthe other station; an indicator in each station controlled by thecurrent in said circuit; and electrically operated locking means,controlled by the current in said circuit and adapted to lock saidsending switch, whereby said sending' switch is prevented from movementunless said receiving switch breaks said circuit.

3. In a system for train control, the combination of two alternatecircuits in each adjacent station, one of said circuits in each stationbeing grounded, the other circuit in each station including a generator;a line wire between the stations; a sending switch in one stationadapted to connect the line wire to either circuit in the said station;a receiving switch in the other station adapted to connect the line wireto either circuit in the said other station, whereby a main circuit iscompleted when one of said switches is connected to the generatorcircuit in its station and the other switch is connected to A thegrounded circuit in its station and is not completed under any othercircumstances; an electrically operated locking means controlled by eachcircuit controlled by said sending switch to lock it in connectiontherewith when said main circuit is completed; and an electricallyoperated locking means controlled by one only of the circuits controlledby said receiving switch to lock it in connection therewith when saidmain circuit is completed.

4. In a system for train control, the conibination of two alternatecircuits in each adjacent station, one of said circuits in each stationbeing grounded, the other circuit in each station including a generator;a line wire between the stations; a sending switch in one stationadapted to connect the line wire to either circuit in the said station;a receiving switch in the other station adapted to connect the line wireto either circuit in the said other station, whereby a main circuit iscompleted when one of said switches is connected to the generatorcircuit in its station and the other switch is connected to the groundedcircuit in its station and is not completed under any othercircumstances; an electrically operated locking means controlled by eachcircuit controlled by said sending switch to lock it in connectiontherewith when said main circuit is completed; and an electricallyoperated locking means controlled by one only of the circuits controlledby said receiving switch to lock it in connection therewith when saidmain circuit is completed; and train-operated means for releasing saidlast locking means.

5. In a system for train control, the combination of a generator; twoalternate circuits in a station; a switch adapted to connect either oneof said circuits to a line wire; an electro-magnet in each of saidcircuits, a common armature for both said electro-magnets; and an indexattached to said armature to indicate the circuit to which the switchhas connected the line wire.

6. In a system for train control, the combination of a generator; twoalternate circuits in a station; a switch adapted to connect either oneof said circuits to a line wire; an electro-magnet in each of saidcircuits; a common armature for both of said electromagncts; a fixedindex card; and a movable index card attached to said armature andadapted to pass in front of said fixed card when one of saidelectro-magnets is energized and to be wholly withdrawn from said indexcard when the other electro-magnet is energized.

7. In a system for train control, the combination of two alternatecircuits in each adjacent station, one of said circuits in each stationbeing grounded,the other circuit in each station including a generator;a line wire between the stations; a sending switch in one stationadapted to connect ythe line wire to either circuit in the said station;a receiving switch in the other station adapted to connect the line wireto either circuit in the said other station; whereby a main circuit iscompleted when one oit said switches is connected to the generatorcircuit in its station and the other switch is connected to the groundedcircuit'in' its station and is not' nate circuits, said electro-magnetsbeing arranged in pairs, one pair ineach station; a common armature forboth electro-magnets ina pair; a fixed indexv card adjacent each pair ofelectro-magnets; and a movable index card attached to each armature andboth adapted to pass in front of said fixed cards when one switch isconnected to the gen: erator circuit so that the current will flow inone direction in the main circuit, and both adapted to be whollywithdrawn from said fixed index cards when the other switch is connectedto the generator circuit so that the current will flow in the otherdirection in the main circuit.

8. In a system for train control, the coinbination of two pairs otalternate circuits in each adjacent station, one circuit of each pair ineach station being grounded, the other circuits in each stationincluding a generator; a sending switch in each station adapted toconnect to either circuit of one pair; a receiving` switch in eachstation adapted to connect to either circuit of the other pair, twoseparate line wires extending from station to station, each wire joiningthe sending switch of one station to the receiving switch of the otherstation and each conipleting a main circuit when a generator circuit ofone station is connected therethrough to a grounded circuit of the otherstation; an electrically operated locking means for each sending switch,controlled by each circuit controlled by said switches, to lock them inconnection with either of their circuits when its main circuit iscompleted; an electrically operated locking means for the receivingswitch in one station controlled by one of its alternate circuits tolock it in connection therewith when its main circuit is completed; andlocking means for the receiving switch of the other station to lock itin connection with the other alternate circuit when the firstreceiving'switch is electrically locked and when the main circuit of theirst receiving switch is completed.

9. In a system for train control, the combination of two pairs ofalternate circuits in each adjacent station, one circuit of each pair ineach station being grounded, the other circuit in each station includinga generator; a sending switch in each station adapted to connect toeither circuit of one pair; a receiving switch in each station adaptedto connect to either circuit of the other pair; two separate line wiresextending from station to station, each wire joining the sending switchof one station to the receiving switch of the other station and eachconipletinef amain circuit when a generator circuit oi? one station isconnected therethrough to a grounded circuit of the other station;

an electrically operated locking means for ij each sending switch,controlled by each circuit controlled by said switches, to lock themv`in connection with either of their circuits when its main circuit iscompleted; an

electrically operated locking means for the receiving switch in onestation controlled by one of its alternate circuits to lock it inconnection therewith when its main circuit is completed; train-operatedmeans for releasing said last locking means; and locking" means for thereceiving switch of the other station to lock it in connection with theother alternate circuit when the first receiving switch is electricallylocked and when the main circuit of the tirst receiving switch iscompleted.

10. In a system for train control, the coinbination of two pairs ofalternate circuits in each adjacent station, one circuit of each pairbeing grounded, the other circuits in each station including agenerator; a sending switch in each station adapted to connect to eithercircuit of one pair; a receiving switch in each station adapted toconnect to either circuit ot the other pair; two separate line wiresextending from station to station, each wire joining the sending switchof one station to the receiving switch ot the other station and eachcompleting a main circuit when a generator circuit of' one station isconnected Vtherethrough tov a grounded circuit in the other station; anelectro-inagnet in each of said eight alternate circuits, saidelectro-magnets being arranged in pairs, one pair for each switch ineach station; a common armature for both electro-magnets in a pair; afixed index card between the pairs of electro-inagnets in each station;a movable index card attached to each armature and adapted to passinfront i ROBERT W. TAYNTON.

Titnesses M. F. MoNiiiL, J. S. ELLswoRTH.

iio

